chr8-89947858-T-A

Position:

• chr8-89947858-T-A

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_002485.5(NBN):​c.1880A>T​(p.Lys627Met) variant causes a missense change. The variant allele was found at a frequency of 0.000000699 in 1,430,254 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 7.0e-7 (0 hom.)
• Consequence: NBN NM_002485.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 3.95

Genes affected

NBN (HGNC:7652): (nibrin) Mutations in this gene are associated with Nijmegen breakage syndrome, an autosomal recessive chromosomal instability syndrome characterized by microcephaly, growth retardation, immunodeficiency, and cancer predisposition. The encoded protein is a member of the MRE11/RAD50 double-strand break repair complex which consists of 5 proteins. This gene product is thought to be involved in DNA double-strand break repair and DNA damage-induced checkpoint activation. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.19113827).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
NBN	NM_002485.5	c.1880A>T	p.Lys627Met	missense_variant	12/16	ENST00000265433.8	NP_002476.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
NBN	ENST00000265433.8	c.1880A>T	p.Lys627Met	missense_variant	12/16	1	NM_002485.5	ENSP00000265433	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.99e-7 AC: 1 AN: 1430254 Hom.: 0 Cov.: 26 AF XY: 0.00 AC XY: 0 AN XY: 711970

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 9.19e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Microcephaly, normal intelligence and immunodeficiency Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 21, 2023

This sequence change replaces lysine, which is basic and polar, with methionine, which is neutral and non-polar, at codon 627 of the NBN protein (p.Lys627Met). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with NBN-related conditions. ClinVar contains an entry for this variant (Variation ID: 216566). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.13
BayesDel_addAF	Benign	-0.085	T
BayesDel_noAF	Benign	-0.36
CADD	Benign	21
DANN	Uncertain	0.99
DEOGEN2	Benign	0.33	T;T;.
Eigen	Benign	-0.022
Eigen_PC	Benign	-0.043
FATHMM_MKL	Uncertain	0.89	D
LIST_S2	Benign	0.72	T;T;T
M_CAP	Benign	0.045	D
MetaRNN	Benign	0.19	T;T;T
MetaSVM	Benign	-0.74	T
MutationAssessor	Benign	2.0	M;.;.
MutationTaster	Benign	0.96	D;D
PrimateAI	Benign	0.45	T
PROVEAN	Benign	-2.0	N;N;.
REVEL	Benign	0.071
Sift	Uncertain	0.0060	D;D;.
Sift4G	Uncertain	0.022	D;D;T
Polyphen		0.93	P;.;.
Vest4		0.44
MutPred		0.28		Loss of ubiquitination at K627 (P = 0.0092);.;.;
MVP		0.80
MPC		0.32
ClinPred		0.85	D
GERP RS		5.1
Varity_R		0.13
gMVP		0.19

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs762174459; hg19: chr8-90960086;